Sound proof mask for hand microphone



4;; 19, 1958 H. L. WEBB 2,848,565

SOUND PROOF MASK FOR HAND MICROPHONE I Filed June 4. 1954 2 Sheets-Sheet 1 INVENTOR ATTORNEY Aug. 39, 1958 H. L. WEBB 28489 SOUND PROOF MASK FOR HAND MICROPHONE Filed June 4, 1954 2 Sheets-Sheet 2 INVENTOR HORAQE L. WEEQ ATTORNEY SDUND PRQ'GF MASK FUR HAND MICRUPHUNE Horace L. Webb, Fairfax, Va.

Application dune d, 195%, Serial No. 434,414

3 Claims. (Cl. 17%188) This invention relates to an ambient sound-excluding receiver of the character used for recording speech in electric dictating machines as in Court reporting and which is generally exemplified by such patents as those issued to me Nos. 2,526,177; 2,572,547; and 2,625,615.

One important object of the instant adaptation is to generally simplify and improve the construction in the interest of sanitary maintenance and to enable especially the casing to be made of more eflicient parts or sections and even as castings, if desired, from plastic materials.

Another object is to provide such a construction wherein a perforated diaphragm may form an integral part of one of the casing sections and serve as a support for both the face-fitting mask and the microphone.

Further it is aimed to provide a receiver of the character described with novel separably-mounted inhalation duct means and a more efficiently mounted control switch.

Still further, I aim to provide such a device which enables correct breathing and has the air passage therethrough controlled by operation of the switch.

Various additional objects and advantages will be pointed out or become apparent from a consideration of the description following, taken in connection with the accompanying drawings, illustrating an operative embodiment. In said drawings:

Fig. 1 is a front elevation of the receiver;

Fig. 2 is an exploded side elevation thereof with certain of the parts shown in section to disclose details;

Fig. 3 is a central longitudinal sectional view through the receiver;

Fig. 4 is a cross-sectional view taken on the line 4-4 of Fig. 3;

Fig. 5 is a detail of the electrical diagram of the parts employed;

Fig. 6 is a fragmentary longitudinal vertical section through a modified form; and

Fig. 7 is an elevation of the right hand end of Fig. 6, partly broken away to disclose details.

Referring specifically to the drawings wherein like reference characters designate like or similar parts throughout the different views, the receiver may generally take any approved form. As shown, it has a hollow casing or barrel generally designated 10, of requisite length and for instance, generally round in cross-section and having a rear section ii and a front section 12. Said sections 11 and 12 are separably connected together by pins 13 on the section ll cooperating with bayonet slots 14 provided in a rim 15 on the section 12, which is of reduced diameter and extends into section ll. Said casing or barrel sections may be made of any desired material, for instance any of the modern plastics, rubber or the equivalout and their construction well adapts them for manufacture as castings. Said front section 12 has a generally inwardly extending dished wall or diaphragm l6 integral therewith which is suitably perforated as at 17 for exhalation of air therethrough. In any suitable if t We s 9 Patented Aug. 19, lSES if; manner, a generally fiat microphone M is carried by said diaphragm 16. For instance, said microphone M is attached to a flexible rubber or plastic sheet 18 which in turn is directly fastened to the diaphragm 16 by any suitable adhesive, bonding agent or otherwise.

A face-fitting mask member is shown at F. This mask member F is flexible to adapt itself for fitting over the dictators mouth and nose for intimate marginal contact with the face, being of rubber or the equivalent, and at 8 either cemented or otherwise permanently or removably secured to the diaphragm l6. Mask F is preferably cut away at 9 to expose microphone M; Section 12 has an exhalation outlet or vent hole at V which is preferably covered by porous sound absorbing material V.

The section 11 is substantially closed at the rear by a lower or convex wall portion 19, a flat inwardly extending wall portion 26 and an upper transverse wall portion 21. Said portions 19, 20 and 21 are integral with the remainder of the rear section 11 and upper wall portion 21 is interiorly continuous to provide a fiat interior surface 22 having an annular groove 23.

Disposed substanially axially of the sections 11 and 12 and usually made of the same material, is a detachable air inhalation duct section generally designated 24. This section 24 includes a hollow inhalation tube 25 open at both ends and whose front end loosely occupies an opening 26 located centrally in the diaphragm 16. At the rear end, air duct section 24 has a laterally extending round attaching plate 27, which is peripherally provided with an annular flange 23 which occupies the groove 23 and detachably and frictionally engages the wall surfaces therein. it is to be noted that the wall 21 is open or perforated at 23 in line with the bore of the inhalation tube 25 and may have atmospheric communication through one or more apertures or openings 29 in wall 20 for inhalation of fresh air to the exclusion of spent air within the casing or barrel.

A preferably moisture-proof electrical switch device of any approved form generally designated S controls the usual operating circuit at contacts a (Fig. 5) in conductors or feed wires 1') and includes a plug P leading from a source of electricity through microphone M to a dictating or sound recording machine (not shown). Conductors b pass through suitable openings 0, d, e, in casing section ll, diaphragm l6, and wall portion 21, respectively.

Said switch S has a movable operating member 30 which is slidably depressible, although the invention may be practiced where the switch operator has an arcuate, universal or other movement. This switch device with its conducting parts suitably insulated is mounted by means of a fastening tube 31 and clamp nuts 32 threaded thereon in an opening of a supporting lug 33 rigid or integral with and extending inwardly from wall portion 19. Said operating member 30 extends slidably through an opening 3P in wall portion 2% and carries terminally and exteriorly thereof an operating head or button 32 located in the rear of the wall portion 21.

Head or button 32 forms a valve means for inhalation holes 29 and to the lower surface of such head is suitably cemented or otherwise fastened one or more layers or sheets 33 of foam rubber, cloth, cellulose or equivalent sound-insulating asket material to engage wall por tion 2d. A coil spring 34 surrounds operating member 3% and bears against tube 31 and an abutment 35 on operating member 3-? and normally urges the switch operator 3d upwardly or outwardly to the position of Fig. 3 wherein the valve means exposes inhalation holes as. Said Fig. 3 shows the parts of switch S in the preferred or open circuit position, rendering it necessary to depress operating member 3% and maintain it depressed asasees to close the electric circuit for dictation, although this arrangement is optional.

Presuming operation, the casing 1% is held by one hand and the mask M contacted with an expanse of the face of the dictator or reporter covering his mouth and nose, and reporting or dictation proceeds when switch S is closed, that is, when operating member 30 is depressed and gasket 33 engages portion 2% and closes openings 29. The gasket 33 in the closed position excludes the entrance of sound through said openings while actually dictating. Under such conditions spent air is discharged or exhaled through openings 17, the interior of the casing about tube 25 and vent V, but when the air in the lungs is expended by speaking and inhaling is in order, the switch is permitted to automatically raise or open under action of spring 34 to the position of Fig. 3, which is the normal position, whence atmospheric air will enter holes 29 and take a path through the opening 28 and duct 25 to the face of the reporter or dictator and thus without admixture with spent air. Unless switch S is closed, fresh air is always available to the reporter and the path for inflow thereof is automatically controlled through the opening and closing of the switch S, that is control of the operation of the microphone M and dictating machine. Inhalation tube 2 5 prevents admixture of fresh air and spent air.

It will be clear that opening 28 with the parts disassembled and air duct section 2% removed, facilitates mounting, adjustment and repair of the switch S. The ease and inexpensive manufacture of the sections ll, 12 and 24, in particular, their connection and disconnection for various purposes to maintain the apparatus sanitary will be apparent.

Various changes may be made within the spirit and scope of the invention as defined by the following claims, for instance as in the modified form of Figs. 6 and 7. Here the structure is the same as shown and described except as to the rear casing or barrel section which is now designated 11'. The equivalent of switch S is here designated S but is normally closed rather than normally open and is mounted as in the other form in a lug 33 integral with and within a hollow cylindrical or knob shaped integral rear end B. Switch S has a depressible stem 30 vertically slidable in a cylindrical wall portion 36 adjacent to one or more inhalation openings 37 pro-- vided in such wall portion which function like the open-- ings 29 of the first form. An arcuate valve 33 is carried by stem 31) and an expansive spring 39 urges said valve upwardly into engagement with wall portion 36, normally closing inhalation openings 3? as well as closing the switch. A gasket 46 like that used at 33 may face the upper surface of valve 38 and exteriorly of the knob, stem 3h has a button or head ll. Thus in this form the switch S is normally closed and inhalation openings are normally closed. To enable inhalation by the dictator, he depresses button 41 and thus opens the switch of dictating circuit and also opens holes 37 for inhalation through knob B, opening 28' and duct 25 to the face of the dictator as in the first form.

What is claimed is:

l. A sound receiver of the class described comprising a casing open for exhalation and in separable sections one of which is a front section and another of which is a rear section, said front section havin a perforated diaphragm, a microphone mounted by said diaphragm, an air duct means within the casing carried by said front section said air duct means being open to the atmosphere for the inlet of air and having an open end extending into said diaphragm, said rear section having inner surface provided with a continuous groove, and means carried by the air conduit means frictionally engaged in said groove.

2. A sound receiver of the class described comprising a casing open for exhalation and in separable sections one of which is a front section and another of which is a rear section, said front section having a perforated diaphragm, a microphone mounted by said diaphragm, an air duct means within the casing carried by said front section said air duct means being open to the atmosphere for the inlet of air and having an open end extending into said diaphragm, said rear section having exterior wall below its top, a control switch for said microphone having an operating member movable through said wall, said well being perforated for pasair into the casing through said conduit means, a heat. on said operating member exteriorly thereof and said head being movable into closing relation i r the perforated portion of said wall.

3. A sound receiver of the class described comprising a casing open for exhalation and in separable sec- 1 runs one of which is a front section and another of which is a rear section, said front section having a perforated diaphragm, a microphone mounted by said diaphragm, an air duct means within the casing carried by said rear section having open ends, one of said open ends extending through said diaphragm, said rear section having an exterior wall below its top, a control switch for said microphone having an operating member movable through said wall, said wall being perforated for passage of air thcrethrough from the atmosphere into the other open end of said air duct means, a head on said operating member exteriorly thereof, said head being movable into closing relation with the perforated portion of said wall, and means normally urging the operating member outwardly to expose said perforated portion.

4-. A sound receiver of the class described comprising a casing open for exhalation and in separable sections, one of which is a front section and another of which is a rear section, said front section having a perforated diaphragm integral therewith and located across one end thereof, a microphone mounted by the receiver, an air duct means within the casing carried by said rear section having open ends, one of said open ends extending through said diaphragm, said diaphragm having an opening receiving said one of said open ends, said rear section having a wall provided with a continuous inner surface having a groove therein, means on the air conduit means entering said groove to detachably connect the air conduit means in place, the rear section having a horizontal wall provided with an opening, said firstmentioned wall having an opening therethrough communicating with the other open end of said air conduit means and second opening, a switch for said microphone having an operating member slidable through said horizontal wall, a head on said operating member exteriorly of the casing, and said head being engageable with the horizontal wall to control inlet of atmospheric air through the first-mentioned opening.

5. A sound receiver of the class described comprising a casing in displaceable sections, two wall means in spaced relation carried by the sections, one of the wall means being a diaphragm, one of the wall means being provided with an opening, a microphone associated with said diaphragm, an air duct primarily for inhalation of atmospheric air open at both ends disposed within the casing carried by one of said wall means and extending removably nto said opening thus providing a space within the casing between said diaphragm and said other wall means to establish communication between said duct and the atmosphere outside of said space adjacent to said other wall means, said diaphragm having an exhalation opening therethrough to said space, and one of said sections having an exhalation opening leading from said space to the atmosphere.

6. A sound receiver of the class described comprising a casing in displaceable sections, a diaphragm disposed across one of the sections provided with an opening, a microphone associated with said diaphragm, the other section having a generally transverse wall means across the same spaced from the diaphragm, an air duct primarily for inhalation of atmospheric air open at both ends disposed within the casing carried by said wall means and extending removably into said opening thus providing a space within the casing between said diaphragm and said wall means, means to establish communication between said duct and the atmosphere outside of said space and adjacent said wall means, said diaphragm having an exhalation opening therethrough to said space, and one of said sections having an exhalation opening leading from the said space to the atmosphere.

7. A sound receiver according to claim 6 having interfitting means between said air duct and that wall means remote to the diaphragm detachably connecting the air duct to the wall means.

8. A sound receiver according to claim 6 wherein said means to establish communication between said duct and the atmosphere comprises a hollow projection on said wall means, said projection having an opening communicating with its space and the atmosphere, and a control member for the microphone mounted by the extension movable into opening and closing relation to the latter opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,508,310 Van Houte Sept. 9, 1924 2,572,547 Webb Oct. 23, 1951 2,625,615 Webb Jan. 13, 1953 2,754,377 Junghans July 10, 1956 2,769,040 Dimattia Oct. 30, 1956 

